I have just successfully upgraded from Fedora 16 to Fedora 17 using the Preupgrade tool. One of the post-upgrade steps suggested here is to "remove unsupported packages".

The guide says to run package-cleanup --orphans to obtain a list of said packages and then yum remove each one.

Rather than blindly do this I thought I'd check to make sure that this wouldn't unintentionally remove any needed dependencies. For example, ModemManager-0.5.3.96-1.fc16.x86_64 is the first package in the list. When I run:

yum remove ModemManager-0.5.3.96-1.fc16.x86_64

I see that it also wants to remove a number of dependencies that look like valid Fedora 17 packages:

@midnightsteel, yum erase package deletes the package and everything that depends on it, as it should. The --nodeps option to rpm tells it not to check for it, and recommending it to newbies is irresponsible. The steps to clean up the RPM database are completely unneeded.
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vonbrandJan 24 '13 at 23:51